--- /dev/null
+// <tr1/boost_shared_ptr.h> -*- C++ -*-
+
+// Copyright (C) 2005 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING. If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction. Specifically, if other files instantiate
+// templates or use macros or inline functions from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License. This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+// shared_count.hpp
+// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
+
+// shared_ptr.hpp
+// Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
+// Copyright (C) 2001, 2002, 2003 Peter Dimov
+
+// weak_ptr.hpp
+// Copyright (C) 2001, 2002, 2003 Peter Dimov
+
+// enable_shared_from_this.hpp
+// Copyright (C) 2002 Peter Dimov
+
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+// GCC Note: based on version 1.32.0 of the Boost library.
+
+/** @file boost_memory.h
+ * This is an internal header file, included by other library headers.
+ * You should not attempt to use it directly.
+ */
+
+#ifndef _BOOST_SHARED_PTR_H
+#define _BOOST_SHARED_PTR_H 1
+
+// namespace std::tr1
+namespace std
+{
+namespace tr1
+{
+
+class bad_weak_ptr : public std::exception
+{
+public:
+
+ virtual char const* what() const throw()
+ {
+ return "tr1::bad_weak_ptr";
+ }
+};
+
+// Helper for exception objects in <tr1/memory>
+// TODO this should be defined in a different file.
+inline void
+__throw_bad_weak_ptr()
+{
+#if __EXCEPTIONS
+ throw bad_weak_ptr();
+#else
+ std::abort();
+#endif
+}
+
+
+template <typename _Tp>
+ struct _Sp_deleter
+ {
+ typedef void result_type;
+ typedef _Tp* argument_type;
+
+ void
+ operator()(_Tp* p) const
+ { delete p; }
+ };
+
+
+class _Sp_counted_base
+{
+public:
+
+ _Sp_counted_base()
+ : _M_use_count(1), _M_weak_count(1)
+ { }
+
+ virtual
+ ~_Sp_counted_base() // nothrow
+ { }
+
+ // dispose() is called when _M_use_count drops to zero, to release
+ // the resources managed by *this.
+ virtual void
+ dispose() = 0; // nothrow
+
+ // destroy() is called when _M_weak_count drops to zero.
+ virtual void
+ destroy() // nothrow
+ {
+ delete this;
+ }
+
+ virtual void*
+ get_deleter(const std::type_info&) = 0;
+
+ void
+ add_ref_copy()
+ {
+ __gnu_cxx::__atomic_add(&_M_use_count, 1);
+ }
+
+ void
+ add_ref_lock()
+ {
+ if (_M_use_count <= 0) // TODO not yet MT safe XXX
+ {
+ __throw_bad_weak_ptr();
+ }
+ __gnu_cxx::__atomic_add(&_M_use_count, 1);
+ }
+
+ void
+ release() // nothrow
+ {
+ if (__gnu_cxx::__exchange_and_add(&_M_use_count, -1) <= 1)
+ {
+ dispose();
+ weak_release();
+ }
+ }
+
+ void
+ weak_add_ref() // nothrow
+ {
+ __gnu_cxx::__atomic_add(&_M_weak_count, 1);
+ }
+
+ void
+ weak_release() // nothrow
+ {
+ if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) <= 1)
+ {
+ destroy();
+ }
+ }
+
+ long
+ use_count() const // nothrow
+ {
+ return _M_use_count; // XXX is this MT safe?
+ }
+
+private:
+
+ _Sp_counted_base(_Sp_counted_base const&);
+ _Sp_counted_base& operator= (_Sp_counted_base const&);
+
+ _Atomic_word _M_use_count; // #shared
+ _Atomic_word _M_weak_count; // #weak + (#shared != 0)
+};
+
+template <typename _Ptr, typename _Deleter>
+class _Sp_counted_base_impl : public _Sp_counted_base
+{
+public:
+
+ /**
+ * @brief
+ * @pre d(p) must not throw.
+ */
+ _Sp_counted_base_impl(_Ptr __p, _Deleter __d)
+ : _M_ptr(__p), _M_del(__d)
+ { }
+
+ virtual void
+ dispose() // nothrow
+ {
+ _M_del(_M_ptr);
+ }
+
+ virtual void*
+ get_deleter(const std::type_info& __ti)
+ {
+ return __ti == typeid(_Deleter) ? &_M_del : 0;
+ }
+
+private:
+ _Sp_counted_base_impl(const _Sp_counted_base_impl&);
+ _Sp_counted_base_impl& operator=(const _Sp_counted_base_impl&);
+
+ _Ptr _M_ptr; // copy constructor must not throw
+ _Deleter _M_del; // copy constructor must not throw
+};
+
+class weak_count;
+
+class shared_count
+{
+private:
+
+ _Sp_counted_base* _M_pi;
+
+ friend class weak_count;
+
+public:
+
+ shared_count()
+ : _M_pi(0) // nothrow
+ { }
+
+ template <typename _Ptr, typename _Deleter>
+ shared_count(_Ptr __p, _Deleter __d)
+ : _M_pi(0)
+ {
+ try
+ {
+ _M_pi = new _Sp_counted_base_impl<_Ptr, _Deleter>(__p, __d);
+ }
+ catch(...)
+ {
+ __d(__p); // delete __p
+ __throw_exception_again;
+ }
+ }
+
+ // auto_ptr<_Tp> is special cased to provide the strong guarantee
+
+ template <typename _Tp>
+ explicit shared_count(std::auto_ptr<_Tp>& __r)
+ : _M_pi(new _Sp_counted_base_impl<_Tp*,_Sp_deleter<_Tp> >(
+ __r.get(), _Sp_deleter<_Tp>()
+ ))
+ { __r.release(); }
+
+ // throws bad_weak_ptr when __r.use_count() == 0
+ explicit shared_count(const weak_count& __r);
+
+ ~shared_count() // nothrow
+ {
+ if (_M_pi != 0)
+ _M_pi->release();
+ }
+
+ shared_count(const shared_count& __r)
+ : _M_pi(__r._M_pi) // nothrow
+ {
+ if (_M_pi != 0)
+ _M_pi->add_ref_copy();
+ }
+
+ shared_count&
+ operator=(const shared_count& __r) // nothrow
+ {
+ _Sp_counted_base* __tmp = __r._M_pi;
+
+ if(__tmp != _M_pi)
+ {
+ if(__tmp != 0)
+ __tmp->add_ref_copy();
+ if(_M_pi != 0)
+ _M_pi->release();
+ _M_pi = __tmp;
+ }
+ return *this;
+ }
+
+ void swap(shared_count& __r) // nothrow
+ {
+ _Sp_counted_base* __tmp = __r._M_pi;
+ __r._M_pi = _M_pi;
+ _M_pi = __tmp;
+ }
+
+ long
+ use_count() const // nothrow
+ { return _M_pi != 0 ? _M_pi->use_count() : 0; }
+
+ bool
+ unique() const // nothrow
+ { return this->use_count() == 1; }
+
+ friend inline bool
+ operator==(const shared_count& __a, const shared_count& __b)
+ { return __a._M_pi == __b._M_pi; }
+
+ friend inline bool
+ operator<(const shared_count& __a, const shared_count& __b)
+ { return std::less<_Sp_counted_base*>()(__a._M_pi, __b._M_pi); }
+
+ void*
+ get_deleter(const std::type_info& __ti) const
+ { return _M_pi ? _M_pi->get_deleter(__ti) : 0; }
+};
+
+
+class weak_count
+{
+private:
+
+ _Sp_counted_base * _M_pi;
+
+ friend class shared_count;
+
+public:
+
+ weak_count()
+ : _M_pi(0) // nothrow
+ { }
+
+ weak_count(const shared_count& __r)
+ : _M_pi(__r._M_pi) // nothrow
+ {
+ if (_M_pi != 0)
+ _M_pi->weak_add_ref();
+ }
+
+ weak_count(const weak_count& __r)
+ : _M_pi(__r._M_pi) // nothrow
+ {
+ if (_M_pi != 0)
+ _M_pi->weak_add_ref();
+ }
+
+ ~weak_count() // nothrow
+ {
+ if (_M_pi != 0)
+ _M_pi->weak_release();
+ }
+
+ weak_count&
+ operator=(const shared_count& __r) // nothrow
+ {
+ _Sp_counted_base* __tmp = __r._M_pi;
+ if (__tmp != 0)
+ __tmp->weak_add_ref();
+ if (_M_pi != 0)
+ _M_pi->weak_release();
+ _M_pi = __tmp;
+
+ return *this;
+ }
+
+ weak_count&
+ operator=(const weak_count& __r) // nothrow
+ {
+ _Sp_counted_base * __tmp = __r._M_pi;
+ if (__tmp != 0)
+ __tmp->weak_add_ref();
+ if (_M_pi != 0)
+ _M_pi->weak_release();
+ _M_pi = __tmp;
+
+ return *this;
+ }
+
+ void
+ swap(weak_count& __r) // nothrow
+ {
+ _Sp_counted_base * __tmp = __r._M_pi;
+ __r._M_pi = _M_pi;
+ _M_pi = __tmp;
+ }
+
+ long
+ use_count() const // nothrow
+ { return _M_pi != 0 ? _M_pi->use_count() : 0; }
+
+ friend inline bool
+ operator==(const weak_count& __a, const weak_count& __b)
+ { return __a._M_pi == __b._M_pi; }
+
+ friend inline bool
+ operator<(const weak_count& __a, const weak_count& __b)
+ { return std::less<_Sp_counted_base*>()(__a._M_pi, __b._M_pi); }
+};
+
+inline
+shared_count::shared_count(const weak_count& __r)
+: _M_pi(__r._M_pi)
+{
+ if (_M_pi != 0)
+ {
+ _M_pi->add_ref_lock();
+ }
+ else
+ {
+ __throw_bad_weak_ptr();
+ }
+}
+
+// fwd decls
+template <typename _Tp> class weak_ptr;
+template <typename _Tp> class enable_shared_from_this;
+
+struct __static_cast_tag {};
+struct __const_cast_tag {};
+struct __dynamic_cast_tag {};
+struct __polymorphic_cast_tag {};
+
+template<class _Tp> struct shared_ptr_traits
+{
+ typedef _Tp & reference;
+};
+
+template<> struct shared_ptr_traits<void>
+{
+ typedef void reference;
+};
+
+template<> struct shared_ptr_traits<void const>
+{
+ typedef void reference;
+};
+
+template<> struct shared_ptr_traits<void volatile>
+{
+ typedef void reference;
+};
+
+template<> struct shared_ptr_traits<void const volatile>
+{
+ typedef void reference;
+};
+
+
+// enable_shared_from_this support
+
+// friend of enable_shared_from_this
+template <typename _Tp1, typename _Tp2>
+ void
+ __enable_shared_from_this( const shared_count& __pn,
+ const enable_shared_from_this<_Tp1>* __pe,
+ const _Tp2* __px );
+
+inline void
+__enable_shared_from_this(const shared_count&, ...)
+{ }
+
+/**
+ * @class shared_ptr <tr1/memory>
+ *
+ * A smart pointer with reference-counted copy semantics.
+ * The object pointed to is deleted when the last shared_ptr pointing to it
+ * is destroyed or reset.
+ */
+
+template <typename _Tp>
+ class shared_ptr
+ {
+ typedef typename shared_ptr_traits<_Tp>::reference _Reference;
+
+ public:
+
+ typedef _Tp element_type;
+
+ /** @brief Construct an empty %shared_ptr.
+ * @post use_count()==0 && get()==0
+ */
+ shared_ptr() : _M_ptr(0), _M_refcount() // never throws
+ { }
+
+ /** @brief Construct a %shared_ptr that owns the pointer @a p.
+ * @param p A pointer that is convertible to element_type*.
+ * @post use_count()==1 && get()==p
+ * @throw std::bad_alloc, in which case @c delete @a p is called.
+ */
+ template <typename _Tp1>
+ explicit shared_ptr(_Tp1* __p)
+ : _M_ptr(__p), _M_refcount(__p, _Sp_deleter<_Tp1>())
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ // __glibcxx_function_requires(_CompleteConcept<_Tp1*>)
+
+ __enable_shared_from_this( _M_refcount, __p, __p );
+ }
+
+ //
+ // Requirements: D's copy constructor and destructor must not throw
+ //
+ // shared_ptr will release p by calling d(p)
+ //
+ /** @brief Construct a %shared_ptr that owns the pointer @a p
+ * and the deleter @a d.
+ * @param p A pointer.
+ * @param d A deleter.
+ * @post use_count()==1 && get()==p
+ * @throw std::bad_alloc, in which case @a d(p) is called.
+ */
+ template <typename _Tp1, typename _Deleter>
+ shared_ptr(_Tp1* __p, _Deleter __d)
+ : _M_ptr(__p), _M_refcount(__p, __d)
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ // TODO requires D is CopyConstructible and d(p) well-formed
+
+ __enable_shared_from_this( _M_refcount, __p, __p );
+ }
+
+ // generated copy constructor, assignment, destructor are fine.
+
+ /** @brief If @a r is empty, constructs an empty %shared_ptr; otherwise
+ * construct a %shared_ptr that shares ownership with @a r.
+ * @param r A %shared_ptr.
+ * @post get()==r.get() && use_count()==r.use_count()
+ * @throw std::bad_alloc, in which case
+ */
+ template <typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r)
+ : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ }
+
+ /** @brief Constructs a %shared_ptr that shares ownership with @a r
+ * and stores a copy of the pointer stored in @a r.
+ * @param r A weak_ptr.
+ * @post use_count()==r.use_count()
+ * @throw bad_weak_ptr when r.expired(),
+ * in which case the constructor has no effect.
+ */
+ template <typename _Tp1>
+ explicit shared_ptr(const weak_ptr<_Tp1>& __r)
+ : _M_refcount(__r._M_refcount) // may throw
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ // it is now safe to copy r__._M_ptr, as _M_refcount(__r._M_refcount)
+ // did not throw
+ _M_ptr = __r._M_ptr;
+ }
+
+ /**
+ * @post use_count()==1 and r.get()==0
+ */
+ template <typename _Tp1>
+ explicit shared_ptr(std::auto_ptr<_Tp1>& __r)
+ : _M_ptr(__r.get()), _M_refcount()
+ {
+ // TODO requires r.release() convertible to _Tp*, Tp1 is complete,
+ // delete r.release() well-formed
+ _Tp1 * __tmp = __r.get();
+ _M_refcount = shared_count(__r);
+
+ __enable_shared_from_this( _M_refcount, __tmp, __tmp );
+ }
+
+ template <typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r, __static_cast_tag)
+ : _M_ptr(static_cast<element_type*>(__r._M_ptr))
+ , _M_refcount(__r._M_refcount)
+ { }
+
+ template <typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r, __const_cast_tag)
+ : _M_ptr(const_cast<element_type*>(__r._M_ptr))
+ , _M_refcount(__r._M_refcount)
+ { }
+
+ template <typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r, __dynamic_cast_tag)
+ : _M_ptr(dynamic_cast<element_type*>(__r._M_ptr))
+ , _M_refcount(__r._M_refcount)
+ {
+ if (_M_ptr == 0) // need to allocate new counter -- the cast failed
+ {
+ _M_refcount = shared_count();
+ }
+ }
+
+ template <typename _Tp1>
+ shared_ptr&
+ operator=(const shared_ptr<_Tp1>& __r) // never throws
+ {
+ _M_ptr = __r._M_ptr;
+ _M_refcount = __r._M_refcount; // shared_count::op= doesn't throw
+ return *this;
+ }
+
+ template <typename _Tp1>
+ shared_ptr&
+ operator=(std::auto_ptr<_Tp1>& __r)
+ {
+ shared_ptr(__r).swap(*this);
+ return *this;
+ }
+
+ void
+ reset() // never throws
+ { shared_ptr().swap(*this); }
+
+ template <typename _Tp1>
+ void
+ reset(_Tp1* __p) // _Tp1 must be complete
+ {
+ _GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr); // catch self-reset errors
+ shared_ptr(__p).swap(*this);
+ }
+
+ template <typename _Tp1, typename _Deleter>
+ void
+ reset(_Tp1 * __p, _Deleter __d)
+ { shared_ptr(__p, __d).swap(*this); }
+
+ // error to instantiate if _Tp is [cv-qual] void
+ _Reference
+ operator*() const // never throws
+ {
+ _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
+ return *_M_ptr;
+ }
+
+ _Tp*
+ operator->() const // never throws
+ {
+ _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
+ return _M_ptr;
+ }
+
+ _Tp*
+ get() const // never throws
+ { return _M_ptr; }
+
+ // implicit conversion to "bool"
+ private:
+ typedef _Tp* shared_ptr::*__unspecified_bool_type;
+
+ public:
+ operator __unspecified_bool_type() const // never throws
+ { return _M_ptr == 0 ? 0 : &shared_ptr::_M_ptr; }
+
+ bool
+ unique() const // never throws
+ { return _M_refcount.unique(); }
+
+ long
+ use_count() const // never throws
+ { return _M_refcount.use_count(); }
+
+ void
+ swap(shared_ptr<_Tp>& __other) // never throws
+ {
+ std::swap(_M_ptr, __other._M_ptr);
+ _M_refcount.swap(__other._M_refcount);
+ }
+
+ private:
+ template <typename _Tp1>
+ bool
+ _M_less(const shared_ptr<_Tp1>& __rhs) const
+ { return _M_refcount < __rhs._M_refcount; }
+
+ void*
+ _M_get_deleter(const std::type_info& __ti) const
+ { return _M_refcount.get_deleter(__ti); }
+
+ template <typename _Tp1> friend class shared_ptr;
+ template <typename _Tp1> friend class weak_ptr;
+
+ // friends injected into enclosing namespace and found by ADL:
+
+ // get_deleter (experimental)
+ template <typename _Del>
+ friend inline _Del*
+ get_deleter(const shared_ptr& __p)
+ { return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); }
+
+ template <typename _Tp1>
+ friend inline bool
+ operator==(const shared_ptr& __a, const shared_ptr<_Tp1>& __b)
+ { return __a.get() == __b.get(); }
+
+ template <typename _Tp1>
+ friend inline bool
+ operator!=(const shared_ptr& __a, const shared_ptr<_Tp1>& __b)
+ { return __a.get() != __b.get(); }
+
+ template <typename _Tp1>
+ friend inline bool
+ operator<(const shared_ptr& __a, const shared_ptr<_Tp1>& __b)
+ { return __a._M_less(__b); }
+
+ _Tp* _M_ptr; // contained pointer
+ shared_count _M_refcount; // reference counter
+ }; // shared_ptr
+
+// 2.2.3.9 shared_ptr casts
+
+/** @warning The seemingly equivalent
+ * <code>shared_ptr<T>(static_cast<T*>(r.get()))</code>
+ * will eventually result in undefined behaviour,
+ * attempting to delete the same object twice.
+ */
+template <typename _Tp, typename _Tp1>
+ shared_ptr<_Tp>
+ static_pointer_cast(const shared_ptr<_Tp1>& __r)
+ {
+ return shared_ptr<_Tp>(__r, __static_cast_tag());
+ }
+
+/** @warning The seemingly equivalent
+ * <code>shared_ptr<T>(const_cast<T*>(r.get()))</code>
+ * will eventually result in undefined behaviour,
+ * attempting to delete the same object twice.
+ */
+template <typename _Tp, typename _Tp1>
+ shared_ptr<_Tp>
+ const_pointer_cast(const shared_ptr<_Tp1>& __r)
+ {
+ return shared_ptr<_Tp>(__r, __const_cast_tag());
+ }
+
+/** @warning The seemingly equivalent
+ * <code>shared_ptr<T>(dynamic_cast<T*>(r.get()))</code>
+ * will eventually result in undefined behaviour,
+ * attempting to delete the same object twice.
+ */
+template <typename _Tp, typename _Tp1>
+ shared_ptr<_Tp>
+ dynamic_pointer_cast(const shared_ptr<_Tp1>& __r)
+ {
+ return shared_ptr<_Tp>(__r, __dynamic_cast_tag());
+ }
+
+// operator<<
+template <typename _Ch, typename _Tr, typename _Tp>
+ std::basic_ostream<_Ch,_Tr>&
+ operator<<(std::basic_ostream<_Ch,_Tr>& __os, const shared_ptr<_Tp>& __p)
+ {
+ __os << __p.get();
+ return __os;
+ }
+
+
+template <typename _Tp>
+ class weak_ptr
+ {
+ public:
+
+ typedef _Tp element_type;
+
+ weak_ptr()
+ : _M_ptr(0), _M_refcount() // never throws
+ { }
+
+ // generated copy constructor, assignment, destructor are fine
+
+ //
+ // The "obvious" converting constructor implementation:
+ //
+ // template<class Y>
+ // weak_ptr(weak_ptr<Y> const & r): _M_ptr(r._M_ptr), _M_refcount(r._M_refcount) // never throws
+ // {
+ // }
+ //
+ // has a serious problem.
+ //
+ // r._M_ptr may already have been invalidated. The _M_ptr(r._M_ptr)
+ // conversion may require access to *r._M_ptr (virtual inheritance).
+ //
+ // It is not possible to avoid spurious access violations since
+ // in multithreaded programs r._M_ptr may be invalidated at any point.
+ //
+
+ template <typename _Tp1>
+ weak_ptr(const weak_ptr<_Tp1>& r)
+ : _M_refcount(r._M_refcount) // never throws
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ _M_ptr = r.lock().get();
+ }
+
+ template <typename _Tp1>
+ weak_ptr(const shared_ptr<_Tp1>& r)
+ : _M_ptr(r._M_ptr), _M_refcount(r._M_refcount) // never throws
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ }
+
+ template <typename _Tp1>
+ weak_ptr&
+ operator=(const weak_ptr<_Tp1>& r) // never throws
+ {
+ _M_ptr = r.lock().get();
+ _M_refcount = r._M_refcount;
+ return *this;
+ }
+
+ template <typename _Tp1>
+ weak_ptr&
+ operator=(const shared_ptr<_Tp1>& r) // never throws
+ {
+ _M_ptr = r._M_ptr;
+ _M_refcount = r._M_refcount;
+ return *this;
+ }
+
+ shared_ptr<_Tp>
+ lock() const // never throws
+ {
+#ifdef __GTHREADS
+
+ // optimization: avoid throw overhead
+ if (expired())
+ {
+ return shared_ptr<element_type>();
+ }
+
+ try
+ {
+ return shared_ptr<element_type>(*this);
+ }
+ catch (const bad_weak_ptr&)
+ {
+ // Q: how can we get here?
+ // A: another thread may have invalidated r after the use_count test above.
+ return shared_ptr<element_type>();
+ }
+
+#else
+
+ // optimization: avoid try/catch overhead when single threaded
+ return expired() ? shared_ptr<element_type>() : shared_ptr<element_type>(*this);
+
+#endif
+ } // XXX MT
+
+
+ long
+ use_count() const // never throws
+ { return _M_refcount.use_count(); }
+
+ bool
+ expired() const // never throws
+ { return _M_refcount.use_count() == 0; }
+
+ void
+ reset() // never throws
+ { weak_ptr().swap(*this); }
+
+ void
+ swap(weak_ptr& __s) // never throws
+ {
+ std::swap(_M_ptr, __s._M_ptr);
+ _M_refcount.swap(__s._M_refcount);
+ }
+
+ private:
+
+ template <typename _Tp1>
+ bool
+ _M_less(const weak_ptr<_Tp1>& __rhs) const
+ { return _M_refcount < __rhs._M_refcount; }
+
+ // used by __enable_shared_from_this
+ void
+ _M_assign(_Tp* __ptr, const shared_count& __refcount)
+ {
+ _M_ptr = __ptr;
+ _M_refcount = __refcount;
+ }
+
+ // friend injected into namespace and found by ADL
+
+ template <typename _Tp1>
+ friend inline bool
+ operator<(const weak_ptr& __lhs, const weak_ptr<_Tp1>& __rhs)
+ { return __lhs._M_less(__rhs); }
+
+ template <typename _Tp1> friend class weak_ptr;
+ template <typename _Tp1> friend class shared_ptr;
+ friend class enable_shared_from_this<_Tp>;
+
+ _Tp* _M_ptr; // contained pointer
+ weak_count _M_refcount; // reference counter
+
+ }; // weak_ptr
+
+
+
+template <typename _Tp>
+ class enable_shared_from_this
+ {
+ protected:
+
+ enable_shared_from_this()
+ { }
+
+ enable_shared_from_this(const enable_shared_from_this&)
+ { }
+
+ enable_shared_from_this&
+ operator=(const enable_shared_from_this&)
+ { return *this; }
+
+ ~enable_shared_from_this()
+ { }
+
+ public:
+
+ shared_ptr<_Tp>
+ shared_from_this()
+ {
+ shared_ptr<_Tp> p(this->_M_weak_this);
+ return p;
+ }
+
+ shared_ptr<const _Tp>
+ shared_from_this() const
+ {
+ shared_ptr<const _Tp> p(this->_M_weak_this);
+ return p;
+ }
+
+ private:
+ template <typename _Tp1>
+ void
+ _M_weak_assign(_Tp1* __p, const shared_count& __n) const
+ { _M_weak_this._M_assign(__p, __n); }
+
+ template <typename _Tp1>
+ friend void
+ __enable_shared_from_this( const shared_count& __pn, const enable_shared_from_this* __pe, const _Tp1* __px)
+ {
+ if(__pe != 0)
+ __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
+ }
+
+ mutable weak_ptr<_Tp> _M_weak_this;
+ };
+
+} // namespace tr1
+
+/**
+ * @brief std::swap() specialisation for shared_ptr.
+ * @relates shared_ptr.
+ */
+template <typename _Tp>
+ inline void
+ swap(tr1::shared_ptr<_Tp>& __a, tr1::shared_ptr<_Tp>& __b)
+ {
+ __a.swap(__b);
+ }
+
+/**
+ * @brief std::swap() specialisation for weak_ptr.
+ * @relates weak_ptr.
+ */
+template <typename _Tp>
+ void
+ swap(tr1::weak_ptr<_Tp>& __a, tr1::weak_ptr<_Tp>& __b)
+ {
+ __a.swap(__b);
+ }
+
+} // namespace std
+
+#endif
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.
-// boost/shared_count.hpp
-// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
-
-// shared_ptr.hpp
-// (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
-// Copyright (c) 2001, 2002, 2003 Peter Dimov
-
-// weak_ptr.hpp
-// Copyright (c) 2001, 2002, 2003 Peter Dimov
-
-// enable_shared_from_this.hpp
-// Copyright (c) 2002 Peter Dimov
-
#ifndef _TR1_MEMORY
#define _TR1_MEMORY 1
#include <new> // std::bad_alloc
#include <typeinfo> // std::type_info in get_deleter
#include <cstddef> // std::size_t
-#include <algorithm> // for std::swap
-#include <iosfwd> // for std::basic_ostream
-#include <cstdlib> // for std::abort
+#include <algorithm> // std::swap
+#include <iosfwd> // std::basic_ostream
+#include <cstdlib> // std::abort
#include <bits/gthr.h>
#include <bits/atomicity.h>
#include <bits/functexcept.h>
#include <debug/debug.h>
-// namespace std::tr1
-namespace std
-{
-namespace tr1
-{
-
-class bad_weak_ptr : public std::exception
-{
-public:
-
- virtual char const* what() const throw()
- {
- return "tr1::bad_weak_ptr";
- }
-};
-
-// Helper for exception objects in <tr1/memory>
-// TODO this should be defined in a different file.
-inline void
-__throw_bad_weak_ptr()
-{
-#if __EXCEPTIONS
- throw bad_weak_ptr();
-#else
- std::abort();
-#endif
-}
-
-
-template <typename _Tp>
- struct _Sp_deleter
- {
- typedef void result_type;
- typedef _Tp* argument_type;
-
- void
- operator()(_Tp* p) const
- { delete p; }
- };
-
-
-class _Sp_counted_base
-{
-public:
-
- _Sp_counted_base()
- : _M_use_count(1), _M_weak_count(1)
- { }
-
- virtual
- ~_Sp_counted_base() // nothrow
- { }
-
- // dispose() is called when _M_use_count drops to zero, to release
- // the resources managed by *this.
- virtual void
- dispose() = 0; // nothrow
-
- // destroy() is called when _M_weak_count drops to zero.
- virtual void
- destroy() // nothrow
- {
- delete this;
- }
-
- virtual void*
- get_deleter(const std::type_info&) = 0;
-
- void
- add_ref_copy()
- {
- __gnu_cxx::__atomic_add(&_M_use_count, 1);
- }
-
- void
- add_ref_lock()
- {
- if (_M_use_count <= 0) // TODO not yet MT safe XXX
- {
- __throw_bad_weak_ptr();
- }
- __gnu_cxx::__atomic_add(&_M_use_count, 1);
- }
-
- void
- release() // nothrow
- {
- if (__gnu_cxx::__exchange_and_add(&_M_use_count, -1) <= 1)
- {
- dispose();
- weak_release();
- }
- }
-
- void
- weak_add_ref() // nothrow
- {
- __gnu_cxx::__atomic_add(&_M_weak_count, 1);
- }
-
- void
- weak_release() // nothrow
- {
- if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) <= 1)
- {
- destroy();
- }
- }
-
- long
- use_count() const // nothrow
- {
- return _M_use_count; // XXX is this MT safe?
- }
-
-private:
-
- _Sp_counted_base(_Sp_counted_base const&);
- _Sp_counted_base& operator= (_Sp_counted_base const&);
-
- _Atomic_word _M_use_count; // #shared
- _Atomic_word _M_weak_count; // #weak + (#shared != 0)
-};
-
-template <typename _Ptr, typename _Deleter>
-class _Sp_counted_base_impl : public _Sp_counted_base
-{
-public:
-
- /**
- * @brief
- * @pre d(p) must not throw.
- */
- _Sp_counted_base_impl(_Ptr __p, _Deleter __d)
- : _M_ptr(__p), _M_del(__d)
- { }
-
- virtual void
- dispose() // nothrow
- {
- _M_del(_M_ptr);
- }
-
- virtual void*
- get_deleter(const std::type_info& __ti)
- {
- return __ti == typeid(_Deleter) ? &_M_del : 0;
- }
-
-private:
- _Sp_counted_base_impl(const _Sp_counted_base_impl&);
- _Sp_counted_base_impl& operator=(const _Sp_counted_base_impl&);
-
- _Ptr _M_ptr; // copy constructor must not throw
- _Deleter _M_del; // copy constructor must not throw
-};
-
-class weak_count;
-
-class shared_count
-{
-private:
-
- _Sp_counted_base* _M_pi;
-
- friend class weak_count;
-
-public:
-
- shared_count()
- : _M_pi(0) // nothrow
- { }
-
- template <typename _Ptr, typename _Deleter>
- shared_count(_Ptr __p, _Deleter __d)
- : _M_pi(0)
- {
- try
- {
- _M_pi = new _Sp_counted_base_impl<_Ptr, _Deleter>(__p, __d);
- }
- catch(...)
- {
- __d(__p); // delete __p
- __throw_exception_again;
- }
- }
-
- // auto_ptr<_Tp> is special cased to provide the strong guarantee
-
- template <typename _Tp>
- explicit shared_count(std::auto_ptr<_Tp>& __r)
- : _M_pi(new _Sp_counted_base_impl<_Tp*,_Sp_deleter<_Tp> >(
- __r.get(), _Sp_deleter<_Tp>()
- ))
- { __r.release(); }
-
- // throws bad_weak_ptr when __r.use_count() == 0
- explicit shared_count(const weak_count& __r);
-
- ~shared_count() // nothrow
- {
- if (_M_pi != 0)
- _M_pi->release();
- }
-
- shared_count(const shared_count& __r)
- : _M_pi(__r._M_pi) // nothrow
- {
- if (_M_pi != 0)
- _M_pi->add_ref_copy();
- }
-
- shared_count&
- operator=(const shared_count& __r) // nothrow
- {
- _Sp_counted_base* __tmp = __r._M_pi;
-
- if(__tmp != _M_pi)
- {
- if(__tmp != 0)
- __tmp->add_ref_copy();
- if(_M_pi != 0)
- _M_pi->release();
- _M_pi = __tmp;
- }
- return *this;
- }
-
- void swap(shared_count& __r) // nothrow
- {
- _Sp_counted_base* __tmp = __r._M_pi;
- __r._M_pi = _M_pi;
- _M_pi = __tmp;
- }
-
- long
- use_count() const // nothrow
- { return _M_pi != 0 ? _M_pi->use_count() : 0; }
-
- bool
- unique() const // nothrow
- { return this->use_count() == 1; }
-
- friend inline bool
- operator==(const shared_count& __a, const shared_count& __b)
- { return __a._M_pi == __b._M_pi; }
-
- friend inline bool
- operator<(const shared_count& __a, const shared_count& __b)
- { return std::less<_Sp_counted_base*>()(__a._M_pi, __b._M_pi); }
-
- void*
- get_deleter(const std::type_info& __ti) const
- { return _M_pi ? _M_pi->get_deleter(__ti) : 0; }
-};
-
-
-class weak_count
-{
-private:
-
- _Sp_counted_base * _M_pi;
-
- friend class shared_count;
-
-public:
-
- weak_count()
- : _M_pi(0) // nothrow
- { }
-
- weak_count(const shared_count& __r)
- : _M_pi(__r._M_pi) // nothrow
- {
- if (_M_pi != 0)
- _M_pi->weak_add_ref();
- }
-
- weak_count(const weak_count& __r)
- : _M_pi(__r._M_pi) // nothrow
- {
- if (_M_pi != 0)
- _M_pi->weak_add_ref();
- }
-
- ~weak_count() // nothrow
- {
- if (_M_pi != 0)
- _M_pi->weak_release();
- }
-
- weak_count&
- operator=(const shared_count& __r) // nothrow
- {
- _Sp_counted_base* __tmp = __r._M_pi;
- if (__tmp != 0)
- __tmp->weak_add_ref();
- if (_M_pi != 0)
- _M_pi->weak_release();
- _M_pi = __tmp;
-
- return *this;
- }
-
- weak_count&
- operator=(const weak_count& __r) // nothrow
- {
- _Sp_counted_base * __tmp = __r._M_pi;
- if (__tmp != 0)
- __tmp->weak_add_ref();
- if (_M_pi != 0)
- _M_pi->weak_release();
- _M_pi = __tmp;
-
- return *this;
- }
-
- void
- swap(weak_count& __r) // nothrow
- {
- _Sp_counted_base * __tmp = __r._M_pi;
- __r._M_pi = _M_pi;
- _M_pi = __tmp;
- }
-
- long
- use_count() const // nothrow
- { return _M_pi != 0 ? _M_pi->use_count() : 0; }
-
- friend inline bool
- operator==(const weak_count& __a, const weak_count& __b)
- { return __a._M_pi == __b._M_pi; }
-
- friend inline bool
- operator<(const weak_count& __a, const weak_count& __b)
- { return std::less<_Sp_counted_base*>()(__a._M_pi, __b._M_pi); }
-};
-
-inline
-shared_count::shared_count(const weak_count& __r)
-: _M_pi(__r._M_pi)
-{
- if (_M_pi != 0)
- {
- _M_pi->add_ref_lock();
- }
- else
- {
- __throw_bad_weak_ptr();
- }
-}
-
-// fwd decls
-template <typename _Tp> class weak_ptr;
-template <typename _Tp> class enable_shared_from_this;
-
-struct __static_cast_tag {};
-struct __const_cast_tag {};
-struct __dynamic_cast_tag {};
-struct __polymorphic_cast_tag {};
-
-template<class _Tp> struct shared_ptr_traits
-{
- typedef _Tp & reference;
-};
-
-template<> struct shared_ptr_traits<void>
-{
- typedef void reference;
-};
-
-template<> struct shared_ptr_traits<void const>
-{
- typedef void reference;
-};
-
-template<> struct shared_ptr_traits<void volatile>
-{
- typedef void reference;
-};
-
-template<> struct shared_ptr_traits<void const volatile>
-{
- typedef void reference;
-};
-
-
-// enable_shared_from_this support
-
-// friend of enable_shared_from_this
-template <typename _Tp1, typename _Tp2>
- void
- __enable_shared_from_this( const shared_count& __pn,
- const enable_shared_from_this<_Tp1>* __pe,
- const _Tp2* __px );
-
-inline void
-__enable_shared_from_this(const shared_count&, ...)
-{ }
-
-/**
- * @class shared_ptr <tr1/memory>
- *
- * A smart pointer with reference-counted copy semantics.
- * The object pointed to is deleted when the last shared_ptr pointing to it
- * is destroyed or reset.
- */
-
-template <typename _Tp>
- class shared_ptr
- {
- typedef typename shared_ptr_traits<_Tp>::reference _Reference;
-
- public:
-
- typedef _Tp element_type;
-
- /** @brief Construct an empty %shared_ptr.
- * @post use_count()==0 && get()==0
- */
- shared_ptr() : _M_ptr(0), _M_refcount() // never throws
- { }
-
- /** @brief Construct a %shared_ptr that owns the pointer @a p.
- * @param p A pointer that is convertible to element_type*.
- * @post use_count()==1 && get()==p
- * @throw std::bad_alloc, in which case @c delete @a p is called.
- */
- template <typename _Tp1>
- explicit shared_ptr(_Tp1* __p)
- : _M_ptr(__p), _M_refcount(__p, _Sp_deleter<_Tp1>())
- {
- __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
- // __glibcxx_function_requires(_CompleteConcept<_Tp1*>)
-
- __enable_shared_from_this( _M_refcount, __p, __p );
- }
-
- //
- // Requirements: D's copy constructor and destructor must not throw
- //
- // shared_ptr will release p by calling d(p)
- //
- /** @brief Construct a %shared_ptr that owns the pointer @a p
- * and the deleter @a d.
- * @param p A pointer.
- * @param d A deleter.
- * @post use_count()==1 && get()==p
- * @throw std::bad_alloc, in which case @a d(p) is called.
- */
- template <typename _Tp1, typename _Deleter>
- shared_ptr(_Tp1* __p, _Deleter __d)
- : _M_ptr(__p), _M_refcount(__p, __d)
- {
- __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
- // TODO requires D is CopyConstructible and d(p) well-formed
-
- __enable_shared_from_this( _M_refcount, __p, __p );
- }
-
- // generated copy constructor, assignment, destructor are fine.
-
- /** @brief If @a r is empty, constructs an empty %shared_ptr; otherwise
- * construct a %shared_ptr that shares ownership with @a r.
- * @param r A %shared_ptr.
- * @post get()==r.get() && use_count()==r.use_count()
- * @throw std::bad_alloc, in which case
- */
- template <typename _Tp1>
- shared_ptr(const shared_ptr<_Tp1>& __r)
- : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
- {
- __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
- }
-
- /** @brief Constructs a %shared_ptr that shares ownership with @a r
- * and stores a copy of the pointer stored in @a r.
- * @param r A weak_ptr.
- * @post use_count()==r.use_count()
- * @throw bad_weak_ptr when r.expired(),
- * in which case the constructor has no effect.
- */
- template <typename _Tp1>
- explicit shared_ptr(const weak_ptr<_Tp1>& __r)
- : _M_refcount(__r._M_refcount) // may throw
- {
- __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
- // it is now safe to copy r__._M_ptr, as _M_refcount(__r._M_refcount)
- // did not throw
- _M_ptr = __r._M_ptr;
- }
-
- /**
- * @post use_count()==1 and r.get()==0
- */
- template <typename _Tp1>
- explicit shared_ptr(std::auto_ptr<_Tp1>& __r)
- : _M_ptr(__r.get()), _M_refcount()
- {
- // TODO requires r.release() convertible to _Tp*, Tp1 is complete,
- // delete r.release() well-formed
- _Tp1 * __tmp = __r.get();
- _M_refcount = shared_count(__r);
-
- __enable_shared_from_this( _M_refcount, __tmp, __tmp );
- }
-
- template <typename _Tp1>
- shared_ptr(const shared_ptr<_Tp1>& __r, __static_cast_tag)
- : _M_ptr(static_cast<element_type*>(__r._M_ptr))
- , _M_refcount(__r._M_refcount)
- { }
-
- template <typename _Tp1>
- shared_ptr(const shared_ptr<_Tp1>& __r, __const_cast_tag)
- : _M_ptr(const_cast<element_type*>(__r._M_ptr))
- , _M_refcount(__r._M_refcount)
- { }
-
- template <typename _Tp1>
- shared_ptr(const shared_ptr<_Tp1>& __r, __dynamic_cast_tag)
- : _M_ptr(dynamic_cast<element_type*>(__r._M_ptr))
- , _M_refcount(__r._M_refcount)
- {
- if (_M_ptr == 0) // need to allocate new counter -- the cast failed
- {
- _M_refcount = shared_count();
- }
- }
-
- template <typename _Tp1>
- shared_ptr&
- operator=(const shared_ptr<_Tp1>& __r) // never throws
- {
- _M_ptr = __r._M_ptr;
- _M_refcount = __r._M_refcount; // shared_count::op= doesn't throw
- return *this;
- }
-
- template <typename _Tp1>
- shared_ptr&
- operator=(std::auto_ptr<_Tp1>& __r)
- {
- shared_ptr(__r).swap(*this);
- return *this;
- }
-
- void
- reset() // never throws
- { shared_ptr().swap(*this); }
-
- template <typename _Tp1>
- void
- reset(_Tp1* __p) // _Tp1 must be complete
- {
- _GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr); // catch self-reset errors
- shared_ptr(__p).swap(*this);
- }
-
- template <typename _Tp1, typename _Deleter>
- void
- reset(_Tp1 * __p, _Deleter __d)
- { shared_ptr(__p, __d).swap(*this); }
-
- // error to instantiate if _Tp is [cv-qual] void
- _Reference
- operator*() const // never throws
- {
- _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
- return *_M_ptr;
- }
-
- _Tp*
- operator->() const // never throws
- {
- _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
- return _M_ptr;
- }
-
- _Tp*
- get() const // never throws
- { return _M_ptr; }
-
- // implicit conversion to "bool"
- private:
- typedef _Tp* shared_ptr::*__unspecified_bool_type;
-
- public:
- operator __unspecified_bool_type() const // never throws
- { return _M_ptr == 0 ? 0 : &shared_ptr::_M_ptr; }
-
- bool
- unique() const // never throws
- { return _M_refcount.unique(); }
-
- long
- use_count() const // never throws
- { return _M_refcount.use_count(); }
-
- void
- swap(shared_ptr<_Tp>& __other) // never throws
- {
- std::swap(_M_ptr, __other._M_ptr);
- _M_refcount.swap(__other._M_refcount);
- }
-
- private:
- template <typename _Tp1>
- bool
- _M_less(const shared_ptr<_Tp1>& __rhs) const
- { return _M_refcount < __rhs._M_refcount; }
-
- void*
- _M_get_deleter(const std::type_info& __ti) const
- { return _M_refcount.get_deleter(__ti); }
-
- template <typename _Tp1> friend class shared_ptr;
- template <typename _Tp1> friend class weak_ptr;
-
- // friends injected into enclosing namespace and found by ADL:
-
- // get_deleter (experimental)
- template <typename _Del>
- friend inline _Del*
- get_deleter(const shared_ptr& __p)
- { return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); }
-
- template <typename _Tp1>
- friend inline bool
- operator==(const shared_ptr& __a, const shared_ptr<_Tp1>& __b)
- { return __a.get() == __b.get(); }
-
- template <typename _Tp1>
- friend inline bool
- operator!=(const shared_ptr& __a, const shared_ptr<_Tp1>& __b)
- { return __a.get() != __b.get(); }
-
- template <typename _Tp1>
- friend inline bool
- operator<(const shared_ptr& __a, const shared_ptr<_Tp1>& __b)
- { return __a._M_less(__b); }
-
- _Tp* _M_ptr; // contained pointer
- shared_count _M_refcount; // reference counter
- }; // shared_ptr
-
-// 2.2.3.9 shared_ptr casts
-
-/** @warning The seemingly equivalent
- * <code>shared_ptr<T>(static_cast<T*>(r.get()))</code>
- * will eventually result in undefined behaviour,
- * attempting to delete the same object twice.
- */
-template <typename _Tp, typename _Tp1>
- shared_ptr<_Tp>
- static_pointer_cast(const shared_ptr<_Tp1>& __r)
- {
- return shared_ptr<_Tp>(__r, __static_cast_tag());
- }
-
-/** @warning The seemingly equivalent
- * <code>shared_ptr<T>(const_cast<T*>(r.get()))</code>
- * will eventually result in undefined behaviour,
- * attempting to delete the same object twice.
- */
-template <typename _Tp, typename _Tp1>
- shared_ptr<_Tp>
- const_pointer_cast(const shared_ptr<_Tp1>& __r)
- {
- return shared_ptr<_Tp>(__r, __const_cast_tag());
- }
-
-/** @warning The seemingly equivalent
- * <code>shared_ptr<T>(dynamic_cast<T*>(r.get()))</code>
- * will eventually result in undefined behaviour,
- * attempting to delete the same object twice.
- */
-template <typename _Tp, typename _Tp1>
- shared_ptr<_Tp>
- dynamic_pointer_cast(const shared_ptr<_Tp1>& __r)
- {
- return shared_ptr<_Tp>(__r, __dynamic_cast_tag());
- }
-
-// operator<<
-template <typename _Ch, typename _Tr, typename _Tp>
- std::basic_ostream<_Ch,_Tr>&
- operator<<(std::basic_ostream<_Ch,_Tr>& __os, const shared_ptr<_Tp>& __p)
- {
- __os << __p.get();
- return __os;
- }
-
-
-template <typename _Tp>
- class weak_ptr
- {
- public:
-
- typedef _Tp element_type;
-
- weak_ptr()
- : _M_ptr(0), _M_refcount() // never throws
- { }
-
- // generated copy constructor, assignment, destructor are fine
-
- //
- // The "obvious" converting constructor implementation:
- //
- // template<class Y>
- // weak_ptr(weak_ptr<Y> const & r): _M_ptr(r._M_ptr), _M_refcount(r._M_refcount) // never throws
- // {
- // }
- //
- // has a serious problem.
- //
- // r._M_ptr may already have been invalidated. The _M_ptr(r._M_ptr)
- // conversion may require access to *r._M_ptr (virtual inheritance).
- //
- // It is not possible to avoid spurious access violations since
- // in multithreaded programs r._M_ptr may be invalidated at any point.
- //
-
- template <typename _Tp1>
- weak_ptr(const weak_ptr<_Tp1>& r)
- : _M_refcount(r._M_refcount) // never throws
- {
- __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
- _M_ptr = r.lock().get();
- }
-
- template <typename _Tp1>
- weak_ptr(const shared_ptr<_Tp1>& r)
- : _M_ptr(r._M_ptr), _M_refcount(r._M_refcount) // never throws
- {
- __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
- }
-
- template <typename _Tp1>
- weak_ptr&
- operator=(const weak_ptr<_Tp1>& r) // never throws
- {
- _M_ptr = r.lock().get();
- _M_refcount = r._M_refcount;
- return *this;
- }
-
- template <typename _Tp1>
- weak_ptr&
- operator=(const shared_ptr<_Tp1>& r) // never throws
- {
- _M_ptr = r._M_ptr;
- _M_refcount = r._M_refcount;
- return *this;
- }
-
- shared_ptr<_Tp>
- lock() const // never throws
- {
-#ifdef __GTHREADS
-
- // optimization: avoid throw overhead
- if (expired())
- {
- return shared_ptr<element_type>();
- }
-
- try
- {
- return shared_ptr<element_type>(*this);
- }
- catch (const bad_weak_ptr&)
- {
- // Q: how can we get here?
- // A: another thread may have invalidated r after the use_count test above.
- return shared_ptr<element_type>();
- }
-
-#else
-
- // optimization: avoid try/catch overhead when single threaded
- return expired() ? shared_ptr<element_type>() : shared_ptr<element_type>(*this);
-
-#endif
- } // XXX MT
-
-
- long
- use_count() const // never throws
- { return _M_refcount.use_count(); }
-
- bool
- expired() const // never throws
- { return _M_refcount.use_count() == 0; }
-
- void
- reset() // never throws
- { weak_ptr().swap(*this); }
-
- void
- swap(weak_ptr& __s) // never throws
- {
- std::swap(_M_ptr, __s._M_ptr);
- _M_refcount.swap(__s._M_refcount);
- }
-
- private:
-
- template <typename _Tp1>
- bool
- _M_less(const weak_ptr<_Tp1>& __rhs) const
- { return _M_refcount < __rhs._M_refcount; }
-
- // used by __enable_shared_from_this
- void
- _M_assign(_Tp* __ptr, const shared_count& __refcount)
- {
- _M_ptr = __ptr;
- _M_refcount = __refcount;
- }
-
- // friend injected into namespace and found by ADL
-
- template <typename _Tp1>
- friend inline bool
- operator<(const weak_ptr& __lhs, const weak_ptr<_Tp1>& __rhs)
- { return __lhs._M_less(__rhs); }
-
- template <typename _Tp1> friend class weak_ptr;
- template <typename _Tp1> friend class shared_ptr;
- friend class enable_shared_from_this<_Tp>;
-
- _Tp* _M_ptr; // contained pointer
- weak_count _M_refcount; // reference counter
-
- }; // weak_ptr
-
-
-
-template <typename _Tp>
- class enable_shared_from_this
- {
- protected:
-
- enable_shared_from_this()
- { }
-
- enable_shared_from_this(const enable_shared_from_this&)
- { }
-
- enable_shared_from_this&
- operator=(const enable_shared_from_this&)
- { return *this; }
-
- ~enable_shared_from_this()
- { }
-
- public:
-
- shared_ptr<_Tp>
- shared_from_this()
- {
- shared_ptr<_Tp> p(this->_M_weak_this);
- return p;
- }
-
- shared_ptr<const _Tp>
- shared_from_this() const
- {
- shared_ptr<const _Tp> p(this->_M_weak_this);
- return p;
- }
-
- private:
- template <typename _Tp1>
- void
- _M_weak_assign(_Tp1* __p, const shared_count& __n) const
- { _M_weak_this._M_assign(__p, __n); }
-
- template <typename _Tp1>
- friend void
- __enable_shared_from_this( const shared_count& __pn, const enable_shared_from_this* __pe, const _Tp1* __px)
- {
- if(__pe != 0)
- __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
- }
-
- mutable weak_ptr<_Tp> _M_weak_this;
- };
-
-} // namespace tr1
-
-/**
- * @brief std::swap() specialisation for shared_ptr.
- * @relates shared_ptr.
- */
-template <typename _Tp>
- inline void
- swap(tr1::shared_ptr<_Tp>& __a, tr1::shared_ptr<_Tp>& __b)
- {
- __a.swap(__b);
- }
-
-/**
- * @brief std::swap() specialisation for weak_ptr.
- * @relates weak_ptr.
- */
-template <typename _Tp>
- void
- swap(tr1::weak_ptr<_Tp>& __a, tr1::weak_ptr<_Tp>& __b)
- {
- __a.swap(__b);
- }
-
-} // namespace std
+#include <tr1/boost_shared_ptr.h>
#endif
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